docs: def advancing(self):
          """A context manager for when time is moving forward one turn at a time.
  
          When used in LiSE, this means that the game is being simulated.
          It changes how the caching works, making it more efficient.
  
          """
          if self._forward:
              raise ValueError("Already advancing")
          self._forward = True
          yield
          self._forward = False